2.1 Basic Architecture

DBTools.h++ is a C++ class library that sits between a database manufacturer's API and your application. The library consists of two tiers:

The core library encapsulates key database concepts in a database-independent manner following SQL standards.

The access libraries correspond to specific database APIs, and implement the full set of classes required by the core library. Classes within the access libraries provide working methods for the core library classes.

This architecture is illustrated in Figure 1:

Figure 1 -- The DBTools.h++ architecture

You can think of DBTools.h++ as a bridge between your application and your database. It provides client/server communications such as logons, connections, and data binding to application variables that go beyond the scope of most SQL implementations. More importantly, DBTools.h++ provides the C++ datatypes and classes that permit flexible, portable database programming.

A database manufacturer's API typically includes a collection of structures and routines designed to manipulate only the kinds of data that can be stored in the manufacturer's database. DBTools.h++ unifies the database domain with your program domain, allowing you to perform database programming using the same types as the rest of your application.

The access libraries and the core library provide database-specific variants of objects to your application that free you from concerns about differences in database semantics and datatypes. This chapter looks at the architecture of DBTools.h++ and shows how it creates a portable, intuitive, object-oriented interface to relational databases.